Risk factors for recurrence include new ischemic stroke, skipping statins

Action Points

A handful of risk factors predicted who did worse with aggressive medical therapy alone for preventing recurrent ischemic stroke in intracranial stenosis, including having an old infarct in the territory of the stenosis, initially presenting with stroke, and not using a statin at enrollment.

Note that study suggests that patients, especially those with the stated risk factors, should be followed very closely, and have frequent monitoring of their risk factors in an effort to prevent another stroke.

A handful of risk factors predicted who did worse with aggressive medical therapy alone for preventing recurrent ischemic stroke in intracranial stenosis, a post-hoc analysis of the SAMMPRIS trial showed.

Those factors include having an old infarct in the territory of the stenosis, initially presenting with stroke, and not using a statin at enrollment, reported Michael Waters, MD, PhD, of the University of Florida in Gainesville, and colleagues online in JAMA Neurology.

"Healthcare providers should understand the risk factors associated with the greatest likelihood of a repeat stroke in particularly high-risk populations," Waters told MedPage Today. "These patients should be followed very closely, and have frequent monitoring of their risk factors in an effort to prevent another stroke."

But 15% of patients in the medical therapy group still experienced stroke or death during 33 months of follow-up in the study.

To determine the baseline features that were associated with a higher rate of these outcomes in the medical arm of the SAMMPRIS trial, the researchers conducted a post-hoc analysis of data from the 227 patients randomized to medical management alone. A total of 82 of these patients were female, and the mean age was 59.5.

In initial bivariate analyses, seven baseline risk factors were associated with worse outcomes, albeit at a P-value less than 0.10:

Being female: hazard ratio 1.9 (95% CI 0.96-3.7)

Having diabetes mellitus: HR 1.8 (95% CI 0.9-3.5)

Not taking a statin at enrollment: HR 2.6 (95% CI 1.2-5.7)

Stroke as the qualifying event: HR 2.5 (95% CI 1.03-6.0)

Rankin grade of 1 or greater: HR 2.3 (95% CI 0.9-5.5)

Old infarct in the territory of the stenotic artery: HR 2.6 (95% CI 1.3-5.1)

Greater than 80% stenosis: HR 1.9 (95% CI 0.9-3.7)

In multivariate analyses, three of those risk factors remained significant, specifically old infarct in the territory (HR 2.6, 95% C, 1.3-5.3, P=0.006), stroke as the qualifying event (HR 3.0, 95% CI 1.1-7.7, P=0.03), and no statin use at enrollment (HR 2.4, 95% CI 1.1-5.2, P=0.03).

The researchers noted that the association between the absence of statin use at enrollment and high risk for recurrent stroke is "somewhat surprising given that virtually all of the patients in the SAMMPRIS trial were prescribed statins at enrollment."

A possible explanation for that finding is that the use of statins before enrollment "may have led to earlier stabilization of the symptomatic atherosclerotic plaque in these patients, which could have lowered their early and longer-term risk for stroke," they wrote.

The study had some limitations, including its post-hoc nature, multiple comparisons, and the limited sample size, which the researchers said was a result of enrollment being stopped early because of the clear superiority of medical treatment, so it's possible that both type I and type II errors were made.

Waters and colleagues said the findings imply that there is "still an urgent need to develop better treatments for this disease, especially in high-risk subgroups that fared particularly poorly with medical therapy alone. The features identified in this analysis will be useful for choosing eligibility criteria for future trials focused on novel therapies for improving the outcome of high-risk patients with intracranial stenosis."

Randall Edgell, MD, of St. Louis University, commented that it's important to look into additional therapies for these high-risk patients.

"Now that high-risk groups of patients with maximally treated ischemic stroke in the setting of intracranial atherosclerotic stenosis have been identified, new medical and/or endovascular treatments will be needed to further reduce risk," said Edgell, who was not involved in the study.

Since the SAMMPRIS trial was completed, endovascular devices have advanced significantly, he said.

"Drug-eluting balloons, more easily deliverable stents, and even bio-absorbable stents hold the promise of further bending the risk curve away from recurrent stroke and should be studied in clinical trials," Edgell told MedPage Today.

The study was funded by the National Institute of Neurological Disorders and Stroke, the NIH, Stryker Neurovascular (formerly Boston Scientific Neurovascular), AstraZeneca, INTERVENT, Walgreens pharmacies, and the San Diego Center for Health Interventions.

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